The shell construction technique used is based on the Monolithic Dome, see the Monolithic Dome Institute. I purchased the airform from them and attended one of their training courses. I modified their airform anchoring technique, but otherwise used their methods. Thanks David, Gary and everyone else at MDI.
Earth anchors were used to hold down the airform while it was inflated
A thin steel ring beam (attached to small earth anchors) was used to hold down the base of the airform
Steel stakes were used to hold the shape of the ring beam
The airform was spread out ready for attachment to the ring beam
The airform was then attached using a steel strip bolted every 8 inches
Once attached, the airform was test inflated. The wooden box in the foreground is an airlock (it also contains the inflation fans)
A view inside the inflated airform showing the tiedowns and large earth anchors
A vapor barrier made of 8 mil oxygen-stabilized polyethylene was placed over the compacted gravel base and sealed at the seams and at the edges
